Hydraulic control system for clamp of paper cutting machine



Jan. 3, 1961 C. THUMIM HYDRAULIC CONTROL SYSTEM FOR CLAMP OF PAPER CUTTING-MACHINE Filed Feb. 4 1957 3 Sheets-Sheet 1 0F CYL/NDEB m/w A i /z 1 l F fi 1 I /6/ I F'-' 7 n 4| fl H6 4 WA Y 4; VAL VE mic/w)- .DOlY/V BOWL" INVENTOR.

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' HYDRAULIC CONTROL SYSTEM FOR CLAMP OF PAPER CUTTING MACHINE Filed Feb. 4, 1957 5 Sheets-Sheet 2 paw/v 24 a; F T4:- E. 23 1 g- L flmz 1i 1 $02355: INVENTOR.

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HYDRAULIC CONTROL SYSTEM FOR CLAMP'OF PAPER CUTTING MACHINE Filed Feb. 4, 1957 3 SheetsSheet 3 AWMM United States Patent HYDRAULIC CONTROL SYSTEM FOR CLAMP OF PAPER CUTTING MACHINE Carl Thumim, Westbury, N.Y., assignor, by mesne assignments, to Miehle-Goss-Dexter, Inc., Chicago, 11].,

a corporation of Delaware Filed Feb. 4, 1957, Ser. No. 638,077

2 Claims. (Cl. 121-38) This invention relates to paper cutting machines and more particularly to a hydraulic pressure system and mechanical linkages for effecting control thereof for the purpose of lowering or raising the automatic clamps of such cutting machines.

It is an object of the invention to provide precise and accurate control for a paper clamp under various operating conditions. It is another object of the invention to provide a system wherein the weight of the clamp is utilized for a rapid initial downward stroke, followed by hydraulic pressure being applied to exert a suitable clamping force. It is an additional object to provide means for conserving power when the machine is standing idle with the clamp in raised position while at the same time preventing the hydraulic fluid from excessive heating. Other objects and features of the invention will be apparent from the detailed description to follow.

Briefly, my invention comprises a hydraulic pressure system having a four way valve under manual control wherein pressure operated valves are utilized to determine maximum pressures utilized in the raising and lowering of the clamp. A mechanical linkage system comprising a foot treadle is used to control the four way valve, so devised as to coact with a cutting knife operating mechanism to maintain the paper pile clamped regardless of the position of the knife.

A detailed description of the hydraulic circuit and the mechanical control system now follows in conjunction with the appended drawings in which:

Figure 1 shows a schematic diagram of the hydraulic system.

Figure 1a shows the path of pressure fluid when the clamp is moving down.

Figure 111 shows the fluid circuit when the clamp is moving up.

Figure 2 shows a section of the principal parts of a typical pressure relief valve as used in various portions of the hydraulic circuit.

Figure 3 shows an elevation of the principal components utilized in a mechanism for controlling the four way valve by means of a foot treadle and for effecting manual movement of the knife on conjunction with control of the clamp.

Figure 4 is an end view of the assembly of components shown in Figure 3. 7

Referring now to Figure l, the hydraulic circuit comprises a tank 10 connected through a pipe 12 to a pump 13 which is connected, as shown, through a proportional filter 16 and a series of pressure relief valves 20, 24, 27 to a manually operable four way spool valve 30 shown diagrammatically only. A check valve 29 is inserted in the line between valves 27 and 30.

The valve 30 controls a double acting hydraulic cylinder 35 having a downside and an upside" as desig nated and having the piston 38 operating an arm 40 which will be understood to actuate the clamp. The ends of the cylinder are both connected to valve 30, the down side of the cylinder being also connected to a prefill pipe 45 through a check valve 47, which prefill pipe will be seen to connect directly to tank 10.

Valve 24 connects to valve 30 by a line 41 having a check valve 42. Valve 27 connects to a valve 30 by a line 43 having a neede valve 44 therein.

A vent pipe 50 connects a port of valve 30 to the tank and valve 20 has a connecting pipe 53 to the vent pipe, while valve 27 has a connecting pipe 56 to the vent pipe, there being a normally open two-way solenoidvalve 60 inserted .in pipe 56 which will be understood to be controlled by a limit switch (not shown) at the top of the path of travel of the clamp, the valve being energized to closed position when the clamp is moving down; A drain line 63 leads from one end of valve 60 to the vent pipe 50.

Referring to the four-way valve 30, which is of conventional construction, it will be understood that the channels symbolized by a, b, c and d direct fluid to either end of the cylinder 35, under manual control depending upon whether it is desired to move the clamp up or down.

The valves 20, 24 and 27 are all of a standard commercial type of re'ief valve as shown in the sectional elevation of Figure 2. Thus, the port 70 may be connected to a source of oil pressure serving as an inlet for the valve, the oil going through the passage 73 and emerging at the port 76. The oil within the passage 73 exerts its pressure against a piston 80 which is biasedby a spring 83 to maintain closure of a valve head 86 so as to block a relief port 89. Normally oil pressure is balanced on both sides of piston 80 by way of a passage 93 leading to a pressure chamber 96 which is connected with a chamber ltlll'at the rear face of the piston. Chamber 96 is closed by a spring biased by-pass valve 103 having a chamber 106 connected by a passageway 110 to the pressure relief outlet 89. The biasing force of the spring 106 may be regulated by a threaded cap 113 to predetermine the pressure in passage 73 for'opening valve 103 to unbalance piston 80 so as to vent passage 73 to outlet 89. A closure plug 116 is utilized whereby chamber 96 is normally closed. However, for purpose of use of the above described relief valve to perform the functions of valve 27, this plug is removed and the pipe connection 56 substituted. Although the valves 20, 24 and 27 are shown as identical in configuration, it will be understood that various commercial types which vary in physical structure may be utilized instead of identical valves. The general structure and operation of each of these valves, however, is exemplified in Figure 2. a

Referring now to Figure 1a, the hydraulic circuit set up within the system for actuating the clamp in a downward direction is illustrated. Thus, oil from tank 10 is pumped through valves 20, 24 and 27 and check valve 29 to four-way valve 30 and thence to the downside of the cylinder through channel b. I the upside of the cylinder takes place through channel a to the tank.

At the initial movement of the piston 38, check valve valve 27 is ineffective because its inlet and outlet are connected to each other at the point x b of valve 30 (Fig. 1a),

through channel and thus disconnected from vent line 50. Inasmuch as the valve 27 is for pressure relief when the clamp is moving upward, it is not desired to have it effective in clamp descending operation. The valve 60 is energized to closed position at this time, valve I 24 controlling pressure for clamping.

Due to the weight of the clamp, which aids in its Egress of oil 'from' descent, the motion of. the clamp is too rapid for the discharge rate of the pump when the check valve 47 opens. Accordingly, there is a partial vacuum in the line at the section 120 indicated in Figure 1b between valves 20 and30. c Y

"When the clamp contacts the paper pile, pressure in the linefrom the pump builds'up to a degree regulated valve 24, and such pressure building up in'the down end of the cylinder effects closure of check valve 47, resulting in clamping force on the pile.

Valve 24 may be set to crack at any desired maximum clamping pressure up to any desired value such as 750 pounds per square inch. However, valve 20 is set to crack at the top value above mentioned, the maximum allowable pressure in the system.

f In the course of. the downward stroke, the amount of oil sucked into the downside of the cylinder decreases as the velocity of the clamp approaches the pump capacity until finally the clamp stops against the paper pile, at which time heavy'p'ressure is exerted by the pump, depending on the setting of valve 24. During the period that the clamp is moving down, the only retardation of motion is by way of restriction afforded through the ghannel a of valve 30. At the end of the downward motion, the piston moves to the extreme right-hand of the cylinder cutting ofif flow of oil to the channel a and, thus to the tank and enters the closed end section of the cylinder which serves as a buffer.

From the above description it will be apparent that there are two sources of oil supply for the downside of the cylinder when the clamp is descending, one source being-from the pump and the other directly from the tank," thus affording rapid descent'until'the paperpile is engaged by the clamp.

When it is desired to move the clamp down slowly by means of a foot pedal; slow operation of valve 30 may permit oil from the upside of the cylinder to escape. Owing to leaks in the ventline'of'valve 24, for example in the spring controlled orifices or pistons used, some oil may'escape and affect the accuracy with which the clamp can be controlled.' Accordingly, where very accurate control is required, the check valve 42 is provided in the line between valve 30 and valve 24 so that oil may escape by way of valve 30 only. i

Referring now to Figure 1b, the path of pressure fiuid in the system for upward movement of the clamp is illustrated. In this instance it will be seen that oil from the tank passes through'the pump 16 and thence through the valves 20, 24, 27, 29 and 30 (channel 'c) to the upside of the cylinder, moving piston 38 to the left. The downside of the piston exhausts through channel d and pipe 5 0to the tank. At this time the valve 24 is ineffective because its inlet and outlet are connected to each other at the point y.

When the clamp reaches its topmost position, it operates the limit switch (not shown) to open the circuit to the'solenoid of valve 60 which eitects a reduction in the pressure at which the valve 27 will open. The opening of valve 27 affords an oil flow through the needle valve effecting a back pressure to maintain the clamp in uppermost position. Thus, the flow from valve 44 goes to channel d of valve 30 affording a back pressure to maintain the clamp in upward or standby position. This arrangement conserves power when the machine is standing idle and also minimizes heating of the oil which would otherwise occur. Valve 44 may be set in the range of from 80 to 120 pounds per square inch for the purpose described above.

i It will be appreciated that as soon as the clamp commences a descending motion, the solenoid of valve 60 is once more energized since the limit switch (not shown) is disengaged.

To summate the operation of the system, for movement of the clamp, pressure fluid is fed from the pump through the passageways 73 of the valves 24 and 27 and 4 thence to the multi-way valve 30 to be conducted to either end of the cylinder, depending on the direction of movement of the piston desired. It will be noted that connection conduit means between the vent ports 89 and a respective end of the cylinder 35 is provided. Thus, when the multi-way valve is in the position shown in Fig. 1a it connects the throughpassageway 73 of valve 27 to the vent port 89 through channel b of multi-way valve 30, thus rendering valve 27 ineifective because any opening of the vent valve head 86 (Fig. 2) will obviously merely connectthe vent port 89 jwith the through passageway 73, thereby shortcircuiti'ng any ventedfiow: How ever, by comparison with Fig. lb, it will be noted that the vent port of valve 27 is now connected through channel d of the multi-way valve 30 and, therefore, excess pressure can vent to drain line 50. Accordingly, pressure relief valve 27 is inefiective when pressure is fed to the down end of the cylinder, but effective when the pressure is fed to the up end of the cylinder. In a similar manner, the pressure relief valve 24 is ineffective by being short circuited through channel cof the multi-way valve 30 when pressure is being fed to the up end of the cylinder, but effective through channel aof the multi-way valve for venting purposes to drain line 50 when pressure is being fed to the down end of the cylinder, all of which will be understood by comparison of Pigs. in and 1b.

Attention is invited to Figures 3 and 4 showing the mechanism used for actuating the spool valve 30. It is understood that a foot treadle (not shown) is utilized for this purpose, being pivoted on shaft 221 and con nected to a link 222 to effect clockwise rotation of "a bell'crank 223, having duplicate sides, by means of a. connecting pin 226. The bell crank is in turn connected to a block 224 through a pin 225. "Block 224will be" understood'to be attached to the spool (not shown) of valve '30. 'When' the foot treadle is actuated, bloc'k224 is pulled to the right, thusshifting the valve spoolto direct fluid for moving the clamp (not shownydown wardly. "Appropriate slots such as 22211,- and additionai lost motion slots as will be'apparent in other elements for effecting independent action are provided so that when the foot treadle is operated other linkage elements are not moved. Likewise, movement of other linkage elements do not aifect the foot treadle.

In manual operation of the knife, a handle (not shown) is keyed to shaft 231 to effect clockwise rotation. Cam' 232 mounted on shaft 231 engages a roller 233 to rotate a lever 234 against a torsion spring counterclockwise. Lever 234 has duplicate sides pivoted on pin 234a carried by the machine frame F. A pin 235 connecting lever 234 with a link 236 is disposed to pull on a double link 236, having a lost motion slot 236a to effect independent action, which in turn pulls the pin 225 to the right to actuate the valve spool, thus permitting the clamp to descend.

When the lever 234 reaches its extreme counterclockwise position, a latching cam 241a carried by latch 241 which is rotative on an adjustable pin 242 drops to enf gage the pin 237 carried by lever 234 to hold the lever 234 in clamp down position. Therefore, even if cam 232 should be rotated in a counterclockwise direction as by the knife operating handle understood'to be keyed to shaft 231, the clamp will remain locked against the paper pile.

Adjustment of latch 241 is obtained by shifting the pin 242 which is carried in a block 248 by means of screws (not shown) and then clamping the block 248 in posi-' tion by means of bolts 300. In case the knife is stopped on the way down by the operator due to a false start and it is desired to unclamp the paper pile, rotation of a handle 247' pivoted on an extension of pin 242 will actuate a finger 247a into position under latch 241; rotating the latch 241 counterclockwise out of latching position;

As the knife approaches the bottom of its stroke, a

hook 244a formed in a slot in a link 244 is shifted to the right to drop over a pin 243 which is carried by latch 241. When the knife starts on its upward stroke, lever 245 which is part of the knife linkage rotates clockwise to pull pin 246 connecting to link 244 to the left. Thus, hook 244a pulls on pin 243 to rotate latch 241 to the disengaged position, at which time a pin 252 carried by the latch 241 pushes on the underside of the link 244 to disengage pin 243 from book 244a. At this time the pin 237 should move immediately to the left due to the return spring in valve 30. If lever 237 is still being held in clamp down position by the manual operating handle, it would be possible for latch 241 to again engage the pin 237 which is not desirable for the clamp would remain locked on *the pile after the knife reached the top of its stroke. To avoil such malfunction, an auxiliary interlocking latch 251 is provided which is biased by a spring 251a to rotate on a pin 253 toward the underside of pin 252 to hold latch 241 out of engagement. Thus, when cam 232 disengages roller 233 as the operating handle is lifted up, lever 234 moves clockwise due to the return spring (not shown) which will be understood to be in valve 30. When lever 234 reaches its extreme clockwise position, pin 235 engages an extension 251a of latch 251 to disengage it from pin 252. Simultaneously, pin 237 has moved under latch 241, this being the normal disengagement position.

Slot 222a permits working the valve 30 by hand without moving the foot treadle. The slot in link 236 permits working valve 30 by foot without moving lever 234 and causing it to be latched. If the latter should occur, the clamp would not rise if the foot treadle were released. Hook 249a engages pin 243 at the beginning of the up stroke of the knife. After the pin is disengaged, it rides in the slot of link 244 for the rest of the stroke.

The power stroke of the knife is effected by conventional means and need not be described herein.

Having thus described my invention, I am aware that various changes may be made without departing from the spirit thereof, and accordingly I do not seek to be limited to the precise illustrations herein given except as set forth in the appended claims.

1. In a system for actuating the clamp of a paper cutting machine, a double-ended piston motor 35 having a reversibly movable piston 38, a pressure relief valve 24, 27, for each end of the motor, a multi-way valve 30, a source of pressure fluid 16, said multi-way valve being connected to feed pressure fluid to and from either end of said motor from said pressure source, said pressure relief valves having connection means to said multi-way valve, said multi-way valve being operable to render one of said pressure relief valves effective to relieve pressure at one end of said cylinder while rendering the other pressure relief valve ineffective to relieve pressure at the other end of said cylinder, depending upon which end of said cylinder is being fed with pressure fluid, wherein the pressure relief valve at that end being fed with pressure fluid is effective to relieve pressure and the other pressure relief valve is ineffective to relieve pressure, said pressure relief valves 24, 27 each having three ports 70, 76, 89, each pressure relief valve comprising a through passage 73 between two of said ports 70, 76, said pressure relief valves being connected in serial order between said pressure source 16 and said multiway valve 30, wherein fluid from said pressure source passes directly through said pressure relief valves by means of said through passages, the third port of each of said pressure relief valves being closed by a pressure relief element operable to open said port upon predetermined excess pressure in said pressure relief valve, said third port 89 of each of said pressure relief valves being connected to a respective end of said double-ended motor and said multiway valve being effective in one position to connect said third port 89 of one of said pressure relief valves with the through passageway 73 thereof, and in another position to connect said third port of said other pressure relief valve with said through passageway 73 thereof, whereby to alternately render one pressure relief valve effective while the other is rendered ineffective for pressure relief purposes, depending upon the position of said multi-Way valve and the end of the double-ended motor to which pressure is being fed.

2. In a system for actuating the clamp of a paper cutting machine, a double-ended piston motor having a reversibly movable piston 38, a pressure relief valve 24, 27, for each end of the motor, a multi-way valve 30, a source of pressure fluid 16, said multi-way valve being connected to feed pressure fluid to and from either end of said motor from said pressure source, said pressure relief valves having connection means to said multi-way valve, said multi-way valve being operable to render one of said pressure relief valves effective to relieve pressure at one end of said cylinder while rendering the other pressure relief valve ineffective to relieve pressure at the other end of said cylinder, depending upon which end of said cylinder is being fed with pressure fluid, wherein the pressure relief valve at that end being fed with pressure fluid is effective to relieve pressure and the other pressure relief valve is ineffective to relieve pressure, said system including a tank 10 and pre-fill means 45, 47 for establishing direct communication for fluid flow from said tank to one end of said cylinder for effecting rapid movement of said piston in one direction of travel thereof, said connection means for one of said pressure relief valves 27 having a restriction means 44 therein to maintain pressure on the piston when said piston is stationary at the end of travel in the same direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,791,013 Rudolph Feb. 3, 1931 2,192,778 Stacy Mar. 5, 1940 2,218,818 Harrington Oct. 22, 1940 2,246,461 Cannon June 17, 1941 2,265,800 Connor et a1. Dec. 9, 1941 2,419,235 Stacy Apr. 22, 1947 2,465,758 Sedgwick et a1 Mar. 29, 1949 2,550,529 Carson et al. Apr. 24, 1951 2,637,353 Hyslop May 5, 1953 

